This invention relates to rapid manufacturing, and more particularly to rapid manufacturing items such as dental prosthetics.
Dental restorations may have multiple, complex structures including layers of various materials with different mechanical and aesthetic properties. This poses significant challenges for conventional rapid prototyping systems. Many fabrication technologies employ a single material, which limits output to monolithic structures. Some layer-additive techniques are capable of producing multi-material structures, such as the system described in U.S. Pat. No. 5,208,431 to Uchiyama et al. However, these technologies also impose limitations. For example, layer-additive technologies based on planar deposition of multiple materials have significant issues related to oxidation, thermal stress, and the like. Planar layer additive technologies can also exhibit poor surface qualities due to z-axis stair stepping or x-y plane terracing. Planar strata are also prone to poor layer adhesion which can compromise structural integrity. On the other hand, rotational deposition systems have been devised for fabrication of optical fiber preforms using various mixes of materials; however, these vapor deposition systems focus on uniform circular geometries and are entirely unsuitable for fabrication of custom, three-dimensional shapes.
There remains a need for a system capable of fabricating complex, multi-material items for use in dentistry or the like.